The medical team who are treating Irish woman Lisa Orsi told her family she suffered "extreme altitude sickness".
In a Facebook post thanking the many friends who have rallied around the family since news of the tragedy emerged, her mother Sharon Orsi explained the family are currently in Singapore and are awaiting the results of some tests they have requested on "our baby".
"We are not expecting anything other than what we already know," Sharon explained.
"Due to the fact that Lisa's illness happened in Java and we are now in Singapore, we have a lot of red tape to get through," she added.
Sharon told friends that they have been in "great contact" with Lisa's medical team who informed the family she suffered from "extreme altitude sickness".
"We spent the day with our baby yesterday as Lisa's Singapore brothers and sisters came to see and visit her, we could not believe the numbers," her mother said.
"Her GAA team have been fantastic and couldn't be any more supportive and we will be eternally grateful to them as we are to you all for your words of encouragement and good wishes. We will thank you all so much."
Sharon added that the family will soon be in contact with the Irish ambassador regarding Lisa's repatriation and will keep in touch about arrangements.
Lisa Orsi collapsed after visiting a volcano with friends in Thailand late last week and doctors have informed her parents there is no hope of her making a recovery.
Lisa had spent the past year in Singapore working as a physiotherapist and had gone on a few days' holiday with friends to Indonesia. She was a staunch sportswoman and set up the Gaelic Lions GAA club in Singapore.
During her trip she trekked up a volcano with her friends, but a few hours later fell ill, collapsing in the shower.
Her friends rushed her to hospital where she underwent tests to detect possible aneurysms, but Lisa's condition deteriorated rapidly and she became critically ill.
Her parents Dennis and Sharon booked emergency flights and rushed to their daughter's bedside, where they have maintained a 24-hour vigil.
Further tests to detect brain activity were not positive and arrangements were made to transfer her to hospital in Singapore, where Lisa's wish to donate her organs was expected to be fulfilled.
Thousands of miles away, her family in Derry, including her grandparents, John and Rosemary Orsi, are struggling with the realisation that they will not see Lisa alive again.
Peter said Lisa's vitality, energy and beauty will live on in the hearts of the hundreds of people who were lucky to have known her. He said: "Over the next day or so, Lisa is being transported by air ambulance to the hospital in Singapore where she worked."